METHOD OF CONTROLLING ROBOT AND ROBOT

• US 20130190926A1
• Filed: 01/18/2013
• Published: 07/25/2013
• Est. Priority Date: 01/20/2012
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: MOTOYOSHI, Masaki, HIRABAYASHI, Tomokazu
• Granted Patent: US 9,120,228 B2
• Time in Patent Office: Days
• US Class Current: 700/254
• CPC Class Codes: B25J 9/1607 Calculation of inertia, jacobian matrixes and inverses
• CPC Class Codes: B25J 9/1653 parameters identification, estimation, stiffness, accuracy, error analysis
• CPC Class Codes: G01P 21/02 of speedometers
• CPC Class Codes: G01P 3/44 for measuring angular speed G01P3/56 takes precedence
• CPC Class Codes: G05B 2219/40597 Measure, calculate angular momentum, gyro of rotating body at end effector
• CPC Class Codes: Y10S 901/02 Arm motion controller

Abstract

A method of controlling a robot includes the steps of calculating a torsional angular velocity of an arm using a difference between an angular velocity detected by a gyro sensor and an angular velocity in a gyro sensor coordinate obtained from information detected by a first encoder and a second encoder, calculating a correction amount of a sensitivity error of the gyro sensor using a variation in the torsional angular velocity, and correcting sensitivity of the gyro sensor using the correction amount of the sensitivity error.

Claims

1. A method of controlling a robot including a motor, an angular sensor adapted to detect a rotational angle of the motor, an arm connected to the motor, and an inertial sensor attached to the arm, the method comprising:

calculating a torsional angular velocity of the arm using a difference between an angular velocity detected by the inertial sensor and an angular velocity in an inertial sensor coordinate obtained from angle information detected by the angular sensor;

calculating a correction amount of sensitivity of the inertial sensor using the torsional angular velocity; and

correcting the sensitivity of the inertial sensor using the correction amount.

2. The method of controlling the robot according to claim 1, wherein

the calculating of a correction amount is performed during a movement of the robot.

3. The method of controlling the robot according to claim 1, wherein

in the calculating of a correction amount, the torsional angular velocity is calculated at predetermined time intervals during a movement of the robot, and a correction amount of a sensitivity error is calculated from a sum of values of the torsional angular velocity, which have been calculated at the time intervals, after termination of the movement.

4. The method of controlling the robot according to claim 1, wherein

in the calculating of a correction amount, a rotational direction of the motor is detected, and then a value of the torsional angular velocity is switched between plus and minus in accordance with the rotational direction.

5. The method of controlling the robot according to claim 1, further comprising:

eliminating an offset error of the inertial sensor,

wherein the calculating of a torsion angular velocity is performed after the eliminating of an offset error.

6. The method of controlling the robot according to claim 1, wherein

in the calculating of a correction amount, the correction amount is calculated using a correction coefficient of the sensitivity of the inertial sensor corresponding to an absolute value of a movement speed of the robot.

7. A robot comprising:

a motor;

an arm connected to and driven by the motor;

an angular sensor adapted to detect a rotational angle of the motor;

an inertial sensor attached to the arm;

a torsional angular velocity calculation section adapted to calculate a torsional angular velocity of the arm using a difference between an angular velocity detected by the inertial sensor and an angular velocity in an inertial sensor coordinate obtained from information detected by the angular sensor;

a sensitivity correction amount calculation section adapted to calculate a sensitivity correction amount of the inertial sensor;

a sensitivity correction section adapted to correct sensitivity using the sensitivity correction amount calculated by the sensitivity correction amount calculation section; and

a movement determination section adapted to determine movement of the arm.

8. A method of controlling a robot comprising:

calculating a velocity of a sensor coordinate system using an acceleration detected by an acceleration sensor;

calculating a distortion velocity from a difference between a velocity of a sensor coordinate system detected by a velocity sensor and a velocity of a sensor coordinate system calculated using the acceleration;

calculating a correction amount of sensitivity of the acceleration sensor using the distortion velocity; and

correcting the sensitivity of the acceleration sensor using the correction amount.

9. The method of controlling the robot according to claim 8, wherein

the calculating of a correction amount is performed during a movement of the robot.

10. The method of controlling the robot according to claim 8, wherein

in the calculating a correction amount, the distortion velocity is calculated at predetermined time intervals during a movement of the robot, and a correction amount of a sensitivity error is calculated from a sum of values of the distortion velocity, which have been calculated at the time intervals, after termination of the movement.

11. The method of controlling the robot according to claim 8, wherein

in the calculating a correction amount, a translation direction of a mounting position of the acceleration sensor is detected, and then a value of the distortion velocity is switched between plus and minus in accordance with the translation direction.

12. The method of controlling the robot according to claim 8, further comprising:

eliminating an offset error of the acceleration sensor,

wherein the calculating of a distortion velocity is performed after the eliminating of an offset error.

13. The method of controlling the robot according to claim 8, wherein

in the calculating of a correction amount, the correction amount is calculated using a correction coefficient of the sensitivity of the acceleration sensor corresponding to an absolute value of a movement speed of the robot.